The Caribbean Plate underlies the Caribbean Sea and Central America off the north coast of South America and therefore is mostly an oceanic tectonic plate. It is prone to frequent tsunamis, volcanic eruptions and occasional earthquakes as it borders the regions of intense seismic activity, namely, the North American Plate, the South American Plate and the Cocos Plate. According to a study, the plate is pushed eastward due to a thick section of the South American Plate called ‘the cratonic keel’ which is about three times thicker than its surroundings. Let us understand the other important facts of the Caribbean Plate in detail.
Concerning its historical background, there are two contending theories. One says that it was formed about ten million years ago in the Pacific Ocean. It happened when North America and South America pushed westward as the Atlantic Ocean widened and were separated by the oceanic crust. As a result, the floor of the Pacific Ocean was subducted between these two continents. As the Caribbean Plate was less dense, it did not subduct, but overrode through the ocean floor and moved eastwards, ultimately losing its connection to the Pacific due to the formation of the Isthmus of Panama about three million years ago.
The Caribbean generally consists of island arcs which include the Greater Antilles, the Lesser Antilles, the Leeward Antilles and the Costa Rica-Panama arc in Central America. Covering an area of about 3,300,000 sq km, it has an average depth of about 2490 m and a maximum depth of about 7680 m in the Cayman Trough.
The Caribbean Plate assumes significance because:
- The eastward migration of the Caribbean Plate about 80 million years ago, led to a volcanic arc that stretched from the northwestern South America to the Yucatan Peninsula. This was subject to constant sea-level fluctuations and technotism, forming the first American land bridge along the eastern and northern boundaries of the Plate.
- Another unique feature of the Plate is that within the Caribbean Plate, it becomes possible to distinguish between subduction related magmatic rocks that occur in the magmatic arcs, ocean basins with present formation of oceanic crust and major collision zones.
As it seems, the Caribbean is not quite calm. Since the past 500 years, the estimated number of Tsunamis is about 75, claiming the lives of approximately 3500 people across the Caribbean Basin. Since 1939, there had been 12 submount volcanic eruptions lurking about 180m below the sea level with a base of about 5km in diameter. An eruption of about 2m-high Tsunami washed into Grenada and Grenadines and lasted for about 24 hours.
